Hi, I have 6 saltwater tanks, and I have ran across the..arg.. red algae a couple of times- especially in a fairly new tank. Here's what I do when that happens. After scraping it I do a 25% water change, I add some dwarf blue leg hermit crabs and some snails- the little sand sifting snails love grazing on it- nassarius obsoleta I think they are called. Turbo snails do good on rocks and glass. I then turn the lights off one hour sooner than normal for two weeks or so and I cut my feeding down by half for that time. If I see some layers forming on the substrate I stir it up just a bit. I do water changes each week then for the next two weeks- of course after I have scrubbed the tank. I know it sounds like a little work but in about 2 weeks the cycle will be broken for that algae and it seems to balance itself then. I usually dont have a problem then. The only other thing I could suggest is a UV sterilizer to reduce algae blooms, but you would still have to scrub the tank to get the algae free moving to get zapped once it goes through the UV sterilizer. I've also have cucumbers help with stirring the substrate, they dont eat algae but they do a good job at stirring the sand which helps alot. I've found them to be very hardy and inexpensive. Good luck!
